Instructions

1. Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.
2. In a medium bowl, whisk together the all-purpose flour, baking powder, and salt until well combined.
3. In a large bowl, cream together the softened unsalted butter and granulated sugar using an electric mixer on medium speed until light and fluffy, about 3-5 minutes.
4. Beat in the egg and vanilla extract until fully incorporated.
5. Gradually add the dry ingredients to the wet mixture, alternating with the milk. Begin and end with the dry ingredients, mixing until just combined.
6. Divide the dough in half. To one half, mix in the cocoa powder until fully incorporated and the dough is uniform in color.
7. Using a spoon or cookie scoop, drop alternating spoonfuls of the vanilla and chocolate dough onto the prepared baking sheet, creating a checkerboard pattern.
8. Bake for 12-15 minutes, or until the edges are lightly golden and the tops are set. Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
9. While the cookies are cooling, prepare the icing. In a small bowl, whisk together the powdered sugar and hot water until smooth and desired consistency is reached.
10. Spread half of each cooled cookie with the vanilla icing and the other half with the chocolate icing, using a knife for smooth application.
11. Allow the icing to set at room temperature before serving.